Turkish police on Wednesday arrested 25 people they accused of using Twitter and social media to stoke anti-government sentiment during protests that have engulfed the country.

Police in Turkey's third city of Izmir said the suspects had been detained for "spreading untrue information" and inciting people to join demonstrations, the state-run agency reported. They were rounded up on Tuesday night. Izmir, in western Turkey, has been the scene of violent clashes between riot police and protesters.

The authorities appear to have taken their cue from Turkey's prime minister, Recep Tayyip Erdogan, who denounced Twitter as a "menace to society", adding: "The best examples of lies can be found there." Turkey's state-run media ignored the protests, at least at first, instead screening documentaries on Hitler and penguins.

Families of those arrested gathered in front of Izmir's police station. They said some of those detained, who are all between 20 and 25 years old, don't have Twitter accounts. They added that some of the tweets in question shared information and phone numbers of volunteer doctors and lawyers. Others said: "There are police in x, don't come here" or "this and that street is blocked" or "let's meet tonight at x" Lawyers for the suspects said the accusations were unfounded. "I have looked at their files and examined their tweets," Sevda Erdan Kilic told Radikal newspaper: "There is nothing to provoke the people [into rioting]. They are sentiments we all share." Another lawyer, Imdat Atas, told CNNTurk: "There is nothing in the indictment that points at a crime. We think that [these arrests have been made] because of the prime minister's comments about Twitter."

The arrests came as a small delegation of conservationists campaigning to save Istanbul's Gezi Park met with deputy prime minister Bulent Arinc in the capital Ankara. Erdogan – the main focus of the protesters' ire – is on a tour of North Africa but arrives back in Istanbul on Thursday. He has previously dismissed his opponents as "looters" and fringe extremists. It is unclear whether he is now willing to back down from his earlier abrasive remarks.

The protesters presented Arinc with a list of demands including a halt to plans to redevelop neighbouring Taksim Square and an end to the use of tear gas, fired liberally by police against peaceful protesters last week.

They also demanded the immediate release of all detained activists, the lifting of restrictions on freedom of expression and assembly, and the sacking of officials including governors and top police officers responsible for the violent crackdown.

The group of academics, architects and environmentalists, known as the "Taksim Solidarity Platform," was formed to protect Taksim Square from development, including the rebuilding of an Ottoman army barracks and a shopping mall. "The steps the government takes from now on will define the course of society's reaction," Eyup Muhcu, the head of a chamber of architects, said on Wednesday after the meeting with Arinc.